Raisaite is a rare copper magnesium selenite mineral occurring as delicate blue acicular sprays. It is found in the oxidized zones of selenium-rich hydrothermal ore deposits and is highly prized by advanced mineral collectors for its vivid color and rarity.

Hardness

2.5

Mohs

Luster

Vitreous

Streak

Pale Blue

Transparency

Translucent

mineralrare

Raisaite

Hardness: 2.5
Luster: Vitreous
Streak: Pale Blue
Transparency: Translucent

Is this raisaite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch raisaite with a known reference. Raisaite sits at Mohs 2.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Raisaite leaves a pale blue streak.
3
Read the luster
Hold the specimen under a strong light. Raisaite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: blue, deep blue.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: acicular crystals, radiating clusters.

Often confused with

Raisaite vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Streak differs, so Raisaite leaves pale blue, Ahlfeldite leaves pinkish-white.

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Often found alongside raisaite

Minerals reported to co-occur with raisaite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: MgCu₂(SeO₃)(OH)₄·2H₂O
Mohs hardness: 2.5
Density: 3.32 g/cm³
Colors: Blue Deep Blue
Streak: Pale Blue
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Acicular Crystals, Radiating Clusters
Cleavage: Perfect
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Selenide Deposits
Typical price: $100-500 thumbnail size

Where rockhounds find raisaite

Classic worldwide localities

El Dragón mine, Potosí, Bolivia

Field-hunting tip

Look in hydrothermal selenide deposits country, the host setting where raisaite typically forms. If you start seeing chalcomenite, ahlfeldite, penroseite in float, you are in the right ground. Field specimens usually show a acicular crystals, radiating clusters habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify raisaite?+

Mohs hardness is 2.5. It typically shows a vitreous luster. The streak is pale blue. Common colors include blue, deep blue.

Where is raisaite found?+

Notable localities include El Dragón mine, Potosí, Bolivia.

How much is raisaite worth?+

Typical asking prices fall in the range of $100-500 thumbnail size. Quality, size, and provenance can move individual specimens well outside that range.

Is raisaite safe to handle?+

It contains toxic constituents. Contains copper and selenium; wash hands thoroughly after handling and avoid inhaling dust or ingesting particles. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like raisaite?+

Raisaite is most often confused with Chalcomenite, Ahlfeldite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with raisaite?+

Raisaite commonly co-occurs with Chalcomenite, Ahlfeldite, Penroseite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does raisaite form in?+

Raisaite typically forms in hydrothermal selenide deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is raisaite used for?+

Raisaite is used in collector.

Find raisaite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.